Rename uint256 tests to numbers

nano/core_test/CMakeLists.txt

@@ -35,6 +35,7 @@ add_executable(
   network_filter.cpp
   network_functions.cpp
   node.cpp
+  numbers.cpp
   object_stream.cpp
   optimistic_scheduler.cpp
   processing_queue.cpp
@@ -55,7 +56,6 @@ add_executable(
   throttle.cpp
   toml.cpp
   timer.cpp
-  uint256_union.cpp
   unchecked_map.cpp
   utility.cpp
   vote_cache.cpp